The hard work ethic of the Milanese spans
the centuries. Their oldest traditions are steeped in methodical
work in the fields.
It was working the land that the Milanese put to use both the
technique of the tenacious Certosini monks and the hydraulic inventions
of Leonardo da Vinci, who lived as a guest of
the Sforza family for many years (1482-1513) and bequeathed the
city with precious practical knowledge such as designs for irrigation
methods in agriculture.

excerpt from page
61

In the 15th century the Dominican church
and convent of Santa Maria delle Grazie
was outside the medieval walls of Milan. It was in its refectory
that, between 1495 and 1497, Leonardo painted

The Last Supper

Along with the Monna Lisa at the Paris Louvre, The Last
Supper is Leonardo's most famous work. It is one of the paintings
most often taken as a symbol of Western Art. It depicts
the instant in which Jesus announces to the apostles that he knows
one of them will betray him. Thanks to the sense of perspective
the painting conveyed, the monks eating in the refectory almost
had the impression they were part of the scene.

The sense of awe inspired by this masterpiece
and the profound interest in it stem also from the enormous problems
that its conservation has always presented. When Leonardo da Vinci
painted The Last Supper he employed a technique different
from the traditional one used to paint wall frescoes. The traditional
technique was to divide the section of wall to be frescoed into
small squares to be painted rapidly one at a time, while the plaster
was still moist, so that the paint and the plaster would dry together.
Leonardo chose a technique which resembled the one commonly employed
to paint on canvas or on wood. This allowed him to paint more
than once over the same surface, so that he could retouch details
and thereby achieve the end result he had in mind.
This method did permit Leonardo to create a wall painting of extraordinary
beauty. Unfortunately, it is also exceptionally vulnerable because
the color painted on dry plaster did not stick as well as it would
have done on moist plaster and is all the more perishable.
When this initial setback is added to the refectory's natural
humidity, to the settling of the wall that supports the painting,
causing cracks, and to the inevitable damage caused by the mere
passage of hundreds of years... you will certainly understand
why the conservation of The Last Supper gives rise to such
heartfelt controversy.